1. Summary of the Invention
This invention relates to reinforced plastic products with decorative surfaces having attractive and depth designs resembling the surfaces of onyx and marble. More particularly, this invention relates to reinforced plastic products which display excellent performance characteristics particularly in applications where their surfaces are contacted with cold or/and hot water, such as bathtubs, wash basins, waterproof pans to be employed as the prefabricated bathroom floor, rowboat hulls, etc.
2. Description of the Prior Art
The great majority of reinforced plastic products heretofore available are uni-colored. However, because such uni-colored products cannot fully meet the consumer's requirements, much development effort has been made in recent years to manufacture reinforced plastic products having an aesthetic appearance.
To decorate the surface of such a product, the printing method and the method involving the use of impregnated paper are known. In the case of the printing method, however, the decorative effect attainable is rather prosaic and only superficial, lacking in the sense of depth which is associated, for instance, with onyx or marble. Moreover, the decorative surfaces obtained by printing are inadequate in water resistance and, particularly when the products are contacted with hot water, are ready to become discolored or faded.
The method of producing a design on the surface of plywood using an impregnated paper, that is the method which comprises superimposing a printing paper saturated with a clear synthetic resin on the surface of a plywood and applying both pressure and heat to the assembly over the paper, has also been found to be unsatisfactory in the manufacture of articles, the surfaces of which are to be contacted with hot water in service, such as bathtubs and wash basins, because of the following and other disadvantages. The first disadvantage is that because the impregnated paper is made of cellulosic fiber, it is inadequate in resistance to hot water. The cellulosic fiber, which is organic, gains in volume when contacted with hot water and, consequently, the exposed surface of the product is roughened with time. Experiments have shown that surface defects are encountered when such products are boiled in water for 100 hours on ends. The second disadvantage is that because the paper has a very dense structure, impregnation with an unsaturated polyester resin cannot be thorough enough and removal of air pockets in the resin impregnation step is also inadequate, with the result that fine blisters of the order of 0.1 to 10 mm are produced on the product surface as demonstrated by the boiling resistance test which is normally performed for checking products of this kind for quality, such blisters detracting from the serviceable life of the product.
This invention provides solutions to the foregoing problems. It is, therefore, an object of this invention to provide a reinforced plastic product comprising, either as a whole or in part, a quadruple-layer construction having a surface presenting one of attractive and shimmering effects resembling the rippling surface of marble or the streaked surface pattern of onyx.
It is another object of this invention to provide an aesthetically decorative reinforced plastic product such that its backing FRP layer is not visible from the face side, with only the aforementioned decorative surface effect being clearly visible from the depth of the construction.
It is still another object of this invention to provide a decorative reinforced plastic product having a protective surface layer which is substantially impermeable to cold and hot water and, hence, free from discoloration or changes in color, besides being highly resistant to impact.
It is another yet object of the invention to provide a decorated plastic product incorporating as a decorative layer a woven, or non-woven fabric which is readily susceptible to impregnation with a synthetic resin and to removal of air pockets.
It is a further object of the invention to provide a decorative reinforced plastic product which is lightweight, tough and durable.
The above and other objects as well as the numerous advantages of this invention will become apparent from the following detailed description made with reference to the accompanying drawing.